"We knew our trail was popular, but we didn't know how popular it was," said Claire Costantino, president of the rail trail association.

That's because anybody entering or exiting the Walkway Over the Hudson on the Highland side passes the Hudson Valley Rail Trail trailhead. The Walkway receives roughly 750,000 visitors each year. Roughly 6 in 10 people passing the trailhead are just using the Walkway, Costantino said, while the remainder are using both the Walkway and the rail trail or just the rail trail.

The Hurley O&W Rail Trail receives 81,000 annual visitors, up from a 2008 estimate of 48,000 yearly visitors. "It's good to see the trail catch fire with the local community," said Steve Rice, chairman of the D&H Canal Heritage Corridor Alliance.

The higher figure is primarily because of different methodology, study authors wrote, since the 2008 method was based on a more temperate climate.

The O&W trail runs 10.5 miles from Hurley south to High Falls, while the Hudson Valley trail runs 3.6 miles from the Walkway to Tony Williams Park in Highland.

More than 60 percent of visitors to the Hudson Valley trail use it for walking, while nearly 30 percent use it for biking.

The Hurley trail has more balanced use, with less than half using it for walking, more than a third using it for biking, and more than 1 in 10 using it for jogging.

Expansions of both rail trails are in the works.

The O&W trail has gotten permission from the two Napanoch prisons, Eastern Correctional and Ulster Correctional, to extend the trail from the Ellenville village line to Kerhonkson, which is expected to open later this year, Rice said. And a 0.6-mile extension of the Hudson Valley trail from Tony Williams Park in Highland northwest to the intersection of Route 299 and New Paltz Road is slated for a 2014 opening, Costantino said.